1. Field of the Invention
Embodiments of the present invention relate to a sheathless connector having a grounding pin which protects against a short circuit and damage upon a backwards insertion of the connector to a host device.
2. Description of the Related Art
The strong growth in demand for portable consumer electronics is driving the need for high-capacity storage devices. Non-volatile semiconductor memory devices, such as flash memory storage cards, are becoming widely used to meet the ever-growing demands on digital information storage and exchange. Their portability, versatility and rugged design, along with their high reliability and large storage capacity, have made such memory devices ideal for use in a wide variety of electronic devices, including for example digital cameras, digital music players, video game consoles, PDAs and cellular telephones.
Equally ubiquitous is the universal serial bus (USB) interface for transferring signals between devices such as those named above and other components such as for example desktop computers and the like. The USB interface is comprised of a male plug and female socket connectors. Plugs generally have one or more pins that are inserted into openings in the mating socket. While there are several types of USB connectors, the most commonly used is the type-A plug on which is a 4-pin connector, surrounded by a shield. A conventional type-A USB plug and socket are shown in cross-section in prior art FIGS. 1 through 3. The conventional USB plug 20 shown in FIG. 1 may for example be attached to an electronic device and includes a base 22 on which is formed a signal power pin 24, a pair of signal pins 26, 28 and a signal ground pin 30. The base and pins are covered by a shroud 32. As seen in FIG. 2, the conventional USB socket 36 may be incorporated in a host device and includes a base 38 and four terminals 40 through 46 formed thereon (shown in phantom lines for clarity). As seen in FIG. 3, the plug may be received within the socket with pins 24 through 30 mating with pins 40 through 46 to allow transfer of signals between the electronic and host devices.
In conventional USB connections, the shroud provides a grounding path for electrostatic charges in the electronic device to be dissipated. However, some low profile USB connective devices are currently being made without the shroud, such as plug 50 shown for example in prior art FIGS. 4 and 5. In order to provide a path to ground in the absence of a sheath, it is known to include a grounding plate 52 on a side of the base opposite the signal pins for contacting the conductive sides of the socket 36. For example, U.S. Pat. No. 6,896,527, entitled, “Slim USB Male Connector with System Grounding,” discloses a USB connective device including signal pins on a first side of the base and a ground plate on the opposite side of the base for providing a path to ground.
However, a drawback to known connectors is that, without a shroud, it is often possible to insert a USB plug into a socket in the wrong orientation, i.e., backwards. That is, as shown in prior art FIG. 6, the plug is inserted so that the pins 24 through 30 face the wrong way. In prior art connectors, such as that disclosed in the '527 patent, a backwards insertion of the plug will result in the plate 52 engaging the power and ground terminals of the host device socket. Connecting the host device grounding terminal with the power terminal via the plate 52 can result in a short circuit and damage to the host device. There is therefore a need of an electrical connector having a grounding path but which does not run the risk of electrical short or damage upon a backward insertion of the connector to a host device.